Samantha Anderson, 13, and her brother, 8-year-old Brayden Anderson, both of Ashland, Mo., were swimming near a dock on the 6.5 mile marker of the Gravois Arm when an unknown source of electricity shocked them. Adults in the area removed the siblings from the water and conducted CPR before emergency personnel arrived.

Both were pronounced dead upon arrival at Lake Regional Hospital.

More details will become available when the Missouri State Highway Patrol Troop F concludes its investigation into what caused the electrocution.